The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
A median sternotomy, or cutting through the breastbone, is one of the most common surgical procedures performed. When first described, the recommended method of closure was to insert steel wires around the severed sternum and twist the ends to hold the two sternal halves tightly together. Today, this method, commonly known as the Cerclage wire method, is still the most common method of sternal closure. However, many problems with this method have been reported. For example, wires have been known to loosen (or even break) over time as the patient returns to everyday activities after surgery. Additionally, it is known that, although Cerclage wires are generally sufficient to maintain the opposing faces of the severed sternum in contact and prevent the severed sternum from separating, i.e., pulling apart such that there is a gap between the opposing faces, Cerclage wires generally do not prevent shear movement of the opposing halves relative to each other along the plane of the osteotomy. Furthermore, closing a median sternotomy in an osteoporotic patient, wherein their bone is resorbed, yielding thin, soft bone, is particularly challenging, because the sternum can be very pliable and the tightening of the Cerclage wires can actually crush the sternum.
Movement at the osteotomy line disrupts revascularization and slows healing. If there are gaps or movement along the osteotomy line, the bone healing can be greatly incumbered. Hence, to achieve optimal healing of the severed sternum, the relative movement of the two sternal halves, in every direction (longitudinal shear, horizontal separation, in-and-out shear, etc.) needs to be prevented, or minimized. Cerclage wires generally prevent horizontal separation (if they do not loosen with stress), however, they do not prevent shear movement between the sternal halves.
Several methods have been attempted to better hold the two sternal halves together, and improve the healing process of the sternum, but none of these has gained wide-spread acceptance in practice.